### equilibrium review

Posted:

**Fri Mar 13, 2020 8:50 am**Could someone help me with number 4 on the UA first review sheet? I am a bit confused as to where to even start with this problem.

Q4. The overall dissociation of oxalic acid, H2C2O4

is represented below. The overall

dissociation constant is also indicated. a) What volume of 0.400 M NaOH is required to

neutralize completely a 5.00 x 10-3

mol sample of pure oxalic acid. b) Give the equations

representing the first and second dissociations of oxalic acid. Calculate the value of the first

dissociation constant, K1

, for oxalic acid if the value of the second dissociation constant, K2

, is 6.40 x 10-5

. c) A strong acid is added to a 0.015 M solution of oxalic acid until the pH is 0.5.

Calculate the [C2O42-] in the resulting solution. (Assume the change in volume is negligible.)

H2C2O4 ⇌ 2H+ + C2O42-

, K = 3.78 x 10-6

Q4. The overall dissociation of oxalic acid, H2C2O4

is represented below. The overall

dissociation constant is also indicated. a) What volume of 0.400 M NaOH is required to

neutralize completely a 5.00 x 10-3

mol sample of pure oxalic acid. b) Give the equations

representing the first and second dissociations of oxalic acid. Calculate the value of the first

dissociation constant, K1

, for oxalic acid if the value of the second dissociation constant, K2

, is 6.40 x 10-5

. c) A strong acid is added to a 0.015 M solution of oxalic acid until the pH is 0.5.

Calculate the [C2O42-] in the resulting solution. (Assume the change in volume is negligible.)

H2C2O4 ⇌ 2H+ + C2O42-

, K = 3.78 x 10-6